DESCRIPTION: The proposed study aims to describe and investigate declines of intact families and increases in one-parent and stepparent families in the U.S. using a life-course perspective. Lifetime sequences of marital and non-marital union entry and exit, having children, and living with or apart from children will be estimated for men's and women's entire parenting-age life courses (from approximately 14 to 59 years old). Comparable estimates are derived for blacks and whites. Estimation is from data from the U.S. Panel Study of Income Dynamics (PSID), with checks also to national birth-registration system data. Logistic regression is used to estimate age-specific family structure, and micro simulation is used to chain these together into lifetime estimates. The consequences for parenting life courses of the "divorce revolution" and of the more recent "non-marital-childbearing revolution" are investigated through 1950 to 1975 cohort comparisons and counter-factual simulations. The two main processes of "father disappearance" will thereby be comprehensively described. Cohorts' distributions of time spent living with own children ("parenting years") will be estimated in both parent-year and child-year units. This permits the analysis of the roles of both fertility (within-union and out-of union) and living arrangements --- between parents (whether the child is born into a two parent family and how long the two-parent family stays intact) and between parents and children (who keeps the children). Measures of variation and concentration of fertility and parenting years will be calculated both across cohort members of a given sex and between sexes. The latter will provide estimates of changes over time in male-female inequality in contributions to parenting.